發布時間:2026-05-02 02:23:06 人氣:234300 來源:
腐蝕對密封件的性能影響很大。由於密封件比主機的零件小,而且更精密,通常要選用比主機封耐腐蝕的材料。
類型1.全麵腐蝕與局部腐蝕。
全麵腐蝕,即零件接觸介質的表麵產生均勻腐蝕,其特征是零件的重量減輕,甚至會全部被腐蝕;失去強度;減低硬度。如用1Cr18Ni9Ti不鏽鋼製作的多彈簧,用於稀硫酸時就會出現這種情況。局部腐蝕,可以簡單地用零件上的蝕斑、蝕(shi)孔(kong)來(lai)判(pan)明(ming)。局(ju)部(bu)腐(fu)蝕(shi)是(shi)多(duo)相(xiang)合(he)金(jin)中(zhong)的(de)某(mou)一(yi)相(xiang)或(huo)單(dan)相(xiang)固(gu)溶(rong)體(ti)的(de)某(mou)一(yi)元(yuan)素(su),被(bei)介(jie)質(zhi)選(xuan)擇(ze)性(xing)溶(rong)解(jie)的(de)腐(fu)蝕(shi)形(xing)態(tai)。例(li)如(ru),鈷(gu)基(ji)硬(ying)質(zhi)合(he)金(jin)用(yong)於(yu)高(gao)溫(wen)強(qiang)堿(jian)中(zhong)時(shi),粘(zhan)結(jie)相(xiang)金(jin)屬(shu)鈷(gu)易(yi)被(bei)腐(fu)蝕(shi),硬(ying)質(zhi)相(xiang)碳(tan)化(hua)鎢(wu)骨(gu)架(jia)失(shi)去(qu)強(qiang)度(du),在(zai)機(ji)械(xie)力(li)的(de)作(zuo)用(yong)下(xia)產(chan)生(sheng)晶(jing)粒(li)剝(bo)落(luo)。又(you)如(ru),反(fan)應(ying)燒(shao)結(jie)碳(tan)化(hua)矽(gui),因(yin)遊(you)離(li)矽(gui)被(bei)腐(fu)蝕(shi)而(er)表(biao)麵(mian)呈(cheng)現(xian)麻(ma)點(dian)(PH>10時)。
chuliqiangfushiliutishi,caiyongwaizhuangshihuoshuangduanmianmifeng,keyizuidaxiandujianqingfushiduimifengjiandeyingxiang,yinweitayugongyiliutixiangjiechudelingjianshuzuishao。zheyeshizaiqiangfushitiaojianxia,xuanzemifengjiegoudeyitiaozuizhongguyaodeyuanze。
類型2.應力腐蝕。
應(ying)力(li)腐(fu)蝕(shi)是(shi)金(jin)屬(shu)材(cai)料(liao)在(zai)承(cheng)受(shou)應(ying)力(li)狀(zhuang)態(tai)下(xia)處(chu)於(yu)腐(fu)蝕(shi)環(huan)境(jing)中(zhong)所(suo)產(chan)生(sheng)的(de)腐(fu)蝕(shi)現(xian)象(xiang)。不(bu)論(lun)是(shi)外(wai)部(bu)載(zai)荷(he)或(huo)殘(can)餘(yu)應(ying)力(li),腐(fu)蝕(shi)都(dou)會(hui)加(jia)劇(ju)。容(rong)易(yi)產(chan)生(sheng)應(ying)力(li)腐(fu)蝕(shi)的(de)材(cai)料(liao)的(de)奧(ao)氏(shi)體(ti)不(bu)鏽(xiu)鋼(gang)、tonghejindeng。yinglifushideguochengyibanshizaijinshubiaomianshangxingchengxuanzexingdefushigoucao,zaijixuchanshengjubufushi,zuihouzaiyinglidezuoyongxia,conggoucaodibuchanshengliewen。dianxingdeshilishi104型福鼎機械密封的傳動套,它的材料為1Cr18Ni9Ti,當dang用yong於yu氨an水shui泵beng上shang時shi,傳chuan動dong套tao的de傳chuan動dong耳er環huan最zui容rong易yi出chu現xian應ying力li腐fu蝕shi裂lie紋wen,使shi耳er環huan損sun壞huai。為wei此ci,將jiang其qi凹ao形xing耳er環huan改gai為wei實shi心xin凸tu耳er,即ji可ke防fang止zhi產chan生sheng這zhe種zhong應ying力li腐fu蝕shi。

類型3.介質腐蝕。
密mi封feng件jian與yu流liu體ti間jian的de高gao速su運yun動dong,致zhi使shi接jie觸chu麵mian上shang發fa生sheng微wei觀guan凹ao凸tu不bu平ping。當dang流liu體ti為wei腐fu蝕shi性xing介jie質zhi時shi,將jiang加jia快kuai密mi封feng接jie觸chu表biao麵mian的de化hua學xue反fan應ying,這zhe種zhong反fan應ying有you時shi是shi有you利li的de,有you時shi是shi有you害hai的de。如ru果guo所suo形xing成cheng的de氧yang化hua層ceng被bei破po壞huai,即ji出chu現xian腐fu蝕shi。由you磨mo損sun與yu磨mo蝕shi的de交jiao替ti作zuo用yong而er造zao成cheng材cai料liao的de破po壞huai稱cheng為wei磨mo蝕shi。通tong常chang磨mo蝕shi對dui福鼎機械密封的非主要元件如彈簧座、推環、環huan座zuo等deng所suo帶dai來lai的de危wei害hai還hai不bu致zhi迅xun速su地di反fan應ying出chu密mi封feng性xing能neng的de變bian化hua,但dan卻que是shi摩mo擦ca副fu失shi效xiao的de主zhu要yao形xing態tai之zhi一yi。為wei此ci,在zai腔qiang腐fu蝕shi性xing介jie質zhi中zhong,摩mo擦ca副fu應ying采cai用yong耐nai腐fu蝕shi性xing能neng好hao的de材cai料liao。如ru采cai用yong99.5%的高純氧化鋁陶瓷,或不含遊離矽的熱壓燒結碳化矽等。
類型4.間隙腐蝕。
當dang介jie質zhi處chu於yu金jin屬shu與yu金jin屬shu會hui非fei金jin屬shu元yuan件jian之zhi間jian,存cun在zai很hen小xiao的de縫feng隙xi時shi,由you於yu介jie質zhi呈cheng滯zhi流liu狀zhuang態tai,會hui引yin起qi縫feng隙xi內nei金jin屬shu的de腐fu蝕shi加jia速su,這zhe種zhong腐fu蝕shi形xing態tai稱cheng為wei間jian隙xi腐fu蝕shi。例li如ru福鼎機械密封彈簧座與軸之間,補償環輔助密封圈與軸之間(當然此處還存在微動磨損)chuxiandegoucaohuoshidianjishidianxingdelizi。jiuqiyuanyin,shiyouyufengneijiezhichuyuzhiliuzhuangtai,shidecanjiafushifanyingdewuzhinanyixiangfengneibuchong,erfengneidefushichanwuyounanyixiangwaikuosan,yushizaochengfengneijiezhisuizhefushidejinxing,zaizuchengdenongdu、PH值等方麵愈來愈和整體介質產生很大差異,結果便導致縫內金屬表麵的腐蝕加劇。
間jian隙xi腐fu蝕shi對dui密mi封feng性xing能neng的de危wei害hai很hen大da,密mi封feng圈quan與yu對dui偶ou軸zhou處chu產chan生sheng溝gou槽cao,將jiang導dao致zhi補bu償chang環huan不bu能neng作zuo軸zhou向xiang位wei移yi,失shi去qu追zhui隨sui性xing使shi端duan麵mian分fen離li而er泄xie漏lou。對dui於yu間jian隙xi腐fu蝕shi,通tong常chang可ke以yi通tong過guo正zheng確que選xuan材cai和he合he理li的de結jie構gou設she計ji予yu以yi減jian輕qing。如ru選xuan用yong具ju有you良liang好hao的de抗kang間jian隙xi腐fu蝕shi性xing能neng的de材cai料liao;在結構設計上應盡可能避免形成縫隙和積液死區;采用自衝洗方式進行循環,使密封腔內的介質處於不斷更換和流動狀態,防止介質組分的濃度變化;長(chang)期(qi)停(ting)用(yong)的(de)機(ji)泵(beng),應(ying)將(jiang)積(ji)液(ye)及(ji)時(shi)排(pai)空(kong)等(deng)等(deng),在(zai)結(jie)構(gou)上(shang)要(yao)完(wan)全(quan)消(xiao)除(chu)間(jian)隙(xi)是(shi)不(bu)可(ke)能(neng)的(de),因(yin)此(ci),一(yi)般(ban)采(cai)用(yong)保(bao)護(hu)性(xing)的(de)軸(zhou)承(cheng),在(zai)其(qi)密(mi)封(feng)圈(quan)安(an)裝(zhuang)部(bu)位(wei)可(ke)噴(pen)塗(tu)耐(nai)腐(fu)蝕(shi)材(cai)料(liao)加(jia)以(yi)防(fang)止(zhi)。
類型5.電化學腐蝕。
實際上,福鼎機械密封的各種腐蝕形態,或多或少都銅電化學腐蝕有關。就福鼎機械密封mocafueryan,changchanghuishoudaodianhuaxuefushideweihai,yinweimocafuzuduichangyongbutongzhongcailiao,dangtamenchuyudianjiezhirongyezhong,youyucailiaoguyoudefushidianweibutong,jiechushijiuhuichuchuxianbutongcailiaozhijiandedianouxiaoying,jiyizhongcailiaodefushihuishoudaocujin,lingyizhongcailiaodefushihuishoudaoyizhi。lirutongyuniegegangzudui,yongyuyanghuaxingjiezhizhongshi,niegegangfashengdianlifenjie。yanshui、海水、稀鹽酸、稀硫酸等都是典型電解質溶液,密封件易於產生電化學腐蝕,因而最好是選擇電位相近的材料或陶瓷與填充玻璃纖維聚四氟乙烯組對。